Single pass duplex document path for a digital scanner

ABSTRACT

A document handling system includes an imaging area; a light source located in proximity to the imaging area; a raster imaging scanning system located in proximity to the imaging area; and a looped document path, located in proximity to the imaging area, having an entrance and an exit. The exit of the looped document path is positioned such that an exiting document is placed upon the imaging area a second time. Alternatively, the document handling system includes a semicircular document path, located in proximity to a first imaging area, having an entrance and an exit; and a second imaging area located in proximity to the exit of the semicircular document path. A bi-directional fiber optic element is located between the first and second imaging areas to transmit light from the light source to the second imaging area and light reflected from the second imaging area to the first imaging area.

BACKGROUND

Conventional automatic duplex documents sheet handling and imagingsystems have increased the effective imaging, scanning, or copying ratefor both sides of sets of duplex documents. Such conventional automaticdocument handlers automatically sequentially feed and image a set or jobof plural duplex (two-sided) document sheets, while at the same, theseconventional document handlers are capable of feeding and copyingsimplex documents (one-side). For example, a conventional automaticdocument feeder, which is particularly suited for imaging the documentselectronically (digitally) while the document is moved past such animaging station with a constant velocity transport, allows for a morecompact and faster imaging document handler as compared to documenthandlers which place the document on a full size platen and hold thedocument stationary while it is scanned by a moving scanner.

A particular difficulty in duplex document handling for electronicimaging is the desirability of having only a single electronic imagingstation. However, that requires inverting or turning over each duplexdocument after imaging one side thereof in order to image the other sideof the duplex document, and/or reorienting the documents for collatedrestacking. In conventional duplex document handling systems, theinversion requirement required several time delays in which no documentside (page) imaging is being accomplished, thus effectively reducing theeffective imaging or duplex document copying rate of the overall system.Thus, it is desirable to provide a duplex document handling system withimproved productivity or throughput rate for electronic documentscanners.

Another problem with conventional automatic duplex documents sheethandling systems is the additional requirement of inverting the documenttwice in the overall document path in order to return the document sheetto the exit tray in the original order and be properly collated. As iswell known, if documents are fed in forward serial order (1 to N pageorder) and are sequentially stacked on top of one another as thedocuments exit the system, regardless of whether the output tray is aseparate tray or the original input tray, the document sheets must bestacked “face down” in order to remain collated and in proper order whenfed in such forward or 1 to N page order. Otherwise, the sheets must beundesirably manually reordered after imaging.

Furthermore, conventional automatic duplex documents sheet handlingsystems have been constructed such that the input tray and the outputtray of a document handler are in a vertical relationship to provide amore compact overall configuration and allow the document inversion pathto be compactly interposed between the overlying upper and lower trays.In the conventional automatic duplex documents sheet handling systemshaving a vertical relationship, simplex documents are restacked facedown and collated if the simplex documents are fed from the top of aface up stack in the input tray. However, this handling of a duplexdocument present a problem in that the duplex documents must be inverteda second time between the imaging of one side and the imaging of theother side of the duplex document. Moreover, a third inversion of theduplex document is required in order to allow the duplex document to berestacked properly collated in the output tray. This third inversioncauses a productivity loss, especially where the inversion is doneutilizing the path through the imaging station, preventing the imagingof any document in that time period.

Another example of a conventional duplex scanning system exposes bothsides of a document while the document is moved along a continuousvelocity path. Conventionally, two scan illumination stations are used,one for each side of the document, with the scanned images of the firstside and the second side following two optical paths but imaged via thesame imaging plane. Such two scan illumination stations require a movingmirror or a moving lens to bring projected images onto a common imagingplane. Optical components in motion can create optical misalignments andvibrations. Such motion is also time consuming and requires precisionmechanisms which may be costly to manufacture.

A further example of a conventional duplex scanning system uses tworaster image scanners in separate imaging planes to image both sides ofthe document to eliminate the need for a moving mirror or a moving lens.This conventional approach increases the manufacturing cost of theimaging system.

A still further example of a conventional duplex scanning system providea system with two exposure stations, one for each side of the paper, butonly one raster image scanner. At each imaging station, the document tobe imaged passes over the top of a platen at each imaging station andlight reflected from the side facing the platen is captured by a lens.The lens for the first imaging station captures the image of the firstside reflected through the platen of the first imaging station. The lensarray for the second imaging station captures the image of the secondside reflected through the platen of the second imaging station and thentransmits that the image to the raster image scanner through the platenof the first imaging station.

Therefore, it is desirable to provide a duplex document scanning systemwith improved productivity or throughput rate for electronic documentscanners. Furthermore, it is desirable to provide a duplex documentscanning system with a document path having a minimum number ofinversions. Also, it is desirable to provide a duplex document scanningsystem with a document path that restacks the documents in a properorder. Moreover, it is desirable to provide a duplex document scanningsystem that utilizes only one raster image scanner, one illuminationsource, and one pass through the document path.

An automatic document handling system includes a first imaging area; alight source located in proximity to the first imaging area; a rasterimaging scanning system located in proximity to the first imaging area;a semicircular document path, located in proximity to the first imagingarea, having an entrance and an exit; a second imaging area located inproximity to the exit of the semicircular document path; and abi-directional fiber optic element located between the first and secondimaging areas. The bi-directional fiber optic element transmits lightfrom the light source to the second imaging area and transmits lightreflected from the second imaging area to the first imaging area.

An automatic document handling system includes a first imaging area; alight source located in proximity to the first imaging area; a rasterimaging scanning system located in proximity to the first imaging area;a semicircular document path, located in proximity to the first imagingarea, having an entrance and an exit; a second imaging area located inproximity to the exit of the semicircular document path; a first fiberoptic element located between the first and second imaging areas; and asecond fiber optic element located between the first and second imagingareas. The first fiber optic element transmits light from the lightsource to the second imaging area and transmits light reflected from thesecond imaging area to the first imaging area.

An automatic document handling system includes an imaging area; a lightsource located in proximity to the imaging area; a raster imagingscanning system located in proximity to the imaging area; and a loopeddocument path, located in proximity to the imaging area, having anentrance and an exit. The exit of the looped document path is positionedsuch that an exiting document is placed upon the imaging area a secondtime.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are only for purposes of illustrating an embodiment and arenot to be construed as limiting, wherein:

FIG. 1 is a diagram depicting scanning side one in a single pass duplexscanner;

FIG. 2 is a diagram depicting preparation for scanning side two in asingle pass duplex scanner;

FIG. 3 is a diagram depicting scanning side two in a single pass duplexscanner;

FIG. 4 is a diagram depicting scanning side one in a single pass duplexscanner;

FIG. 5 is a diagram depicting preparation for scanning side two in asingle pass duplex scanner; and

FIG. 6 is a diagram depicting scanning side two in a single pass duplexscanner.

DETAILED DESCRIPTION

For a general understanding, reference is made to the drawings. In thedrawings, like references have been used throughout to designateidentical or equivalent elements. It is also noted that the drawings maynot be drawn to scale and that certain regions may have been purposelydrawn disproportionately so that the features and concepts could beproperly illustrated.

As noted above, it is desirable to provide a duplex document scanningsystem with improved productivity or throughput rate for electronicdocument scanners. Furthermore, it is desirable to provide a duplexdocument scanning system with a document path having a minimum number ofinversions. Also, it is desirable to provide a duplex document scanningsystem with a document path that restacks the documents in a properorder. Moreover, it is desirable to provide a duplex document scanningsystem that utilizes only one raster image scanner, one illuminationsource, and one pass through the document path.

FIG. 1 illustrates an example of a duplex document scanning system. Asillustrated in FIG. 1, the duplex document scanning system includes adigital scanning system 200 having a raster image scanner 225 with anaccompanying light source 250. A document 100 is transported from aninput tray or input staging area 800 to a first imaging area. The lightsource 250 illuminates a first side (A) of the document 100 through afirst transparent platen 275. The first imaging area includes the firsttransparent platen 275 for imaging or scanning the document 100.

The first transparent platen 275 may be a full document platen wherein,after the document 100 is placed thereon, the digital scanning system200 is moved across the first side (A) of the document 100 to generatesuccessive scanlines of image data.

In a different configuration, the first transparent platen 275 may be apartial document platen wherein the digital scanning system 200 isstationary and the document 100, first side (A) facing the stationarydigital scanning system 200, is moved across, at a constant velocity,the stationary digital scanning system 200 to generate successivescanlines of image data.

The successive scanlines of image data result from light 254 from thelight source 250 illuminating the first side (A) of the document 100,light 256 being reflected therefrom, down through the first transparentplaten 275, to the raster image scanner 225. The raster image scanner225 may be a charge-coupled device or a full-width array.

The duplex document scanning system further includes a semicirculardocument path 300 that receives the document 100 exiting the firstimaging area. The semicircular document path 300 provides a mechanismfor inverting the document 100 before the document enters a secondimaging area. The second imaging area includes a second transparentplaten 500. In the second scanning area, a second side (B) of thedocument 100 faces the second transparent platen 500 and the digitalscanning system 200. Thereafter, the document 100 is transported fromthe second imaging area to an output tray or output staging area 700.

The second transparent platen 500 may be a full document platen wherein,after the document 100 is placed thereon, the digital scanning system200 is moved across the second side (B) of the document 100 to generatesuccessive scanlines of image data.

In a different configuration, the second transparent platen 500 may be apartial document platen wherein the digital scanning system 200 isstationary and the document 100, second side (B) facing the stationarydigital scanning system 200, is moved across, at a constant velocity,the stationary digital scanning system 200 to generate successivescanlines of image data.

It is noted that the duplex document scanning system further includesvarious rollers, nips, and drive motors (not shown) to enable the propertransporting of the document 100 from the input tray or input stagingarea 800 to an output tray or output staging area 700.

Between the first and second imaging areas, a fiber optic element 400 islocated. The fiber optic element 400 may be a single fiber optic elementthat is capable of both transmitting light from the light source 250 tothe second imaging area and transmitting reflected light from the secondimaging area to the raster image scanner 225. In a different variation,the fiber optic element 400 may be two fiber optic elements, one capableof transmitting light from the light source 250 to the second imagingarea and the other capable of transmitting reflected light from thesecond imaging area to the raster image scanner 225.

The duplex document scanning system also includes a background area orcover 600 for providing a background to enable document edge detectionby the raster image scanner 225. The background area or cover 600 mayalso include a calibration target to provide the raster image scanner225 with a reference for “absolute white.”

It is noted that this calibration target may be located above the secondtransparent platen 500 since imaging of the light reflected from thecalibration target will pass through both the first and second and lowertransparent platens (275 and 500).

It is also noted that the above-described duplex document scanningsystem requires that a set of duplex originals be placed “face up” inthe input tray and fed in 1 to N order. The multi-page document willthen be delivered “face down” in the output tray but still in the properorder.

As illustrated in FIG. 1, the document 100 is transported from an inputtray or input staging area 800 to a first imaging area. Morespecifically, the first side (A) of the document 100 is transported tothe first transparent platen 275. The light source 250 illuminates thefirst side (A) of the document 100, with light 254, through the firsttransparent platen 275.

In a first configuration, the raster image scanner 225 progressivelyscans, receives reflected light 256, the first side (A) of the document100 as the first side (A) of the document 100 passes over, at a constantvelocity, the stationary raster image scanner 225. In a secondconfiguration, the raster image scanner 225 progressively scans,receives reflected light 256, the first side (A) of the document 100 asraster image scanner 225 passes across the first side (A) of thestationary document 100.

As illustrated in FIG. 2, as the first side (A) of the document 100exits the first imaging area, the document 100 enters the semicirculardocument path 300. The semicircular document path 300 inverts thedocument 100 with respect to the raster image scanner 225 withoutstopping the motion of the document 100 or reversal of the forwardmomentum of the document 100.

As illustrated in FIG. 3, the document 100 is transported from an exitof the semicircular document path 300 to a second imaging area. Morespecifically, the second side (B) of the document 100 is transported tothe second transparent platen 500. The light source 250 illuminates thesecond side (B) of the document 100, with light 254, through the firsttransparent platen 275.

In a first configuration, the raster image scanner 225 progressivelyscans, receives reflected light 256, the second side (B) of the document100 as the second side (B) of the document 100 passes over, at aconstant velocity, the stationary raster image scanner 225. In a secondconfiguration, the raster image scanner 225 progressively scans,receives reflected light 256, the second side (B) of the document 100 asraster image scanner 225 passes across the second side (B) of thestationary document 100. Thereafter, the document 100 is transportedfrom the second imaging area to an output tray or output staging area700.

As illustrated in FIG. 3, the second side (B) of the stationary document100 is illuminated by light 254 from light source 250 through the firsttransparent platen 275, the fiber optic element 400, and the secondtransparent platen 500. The light 256 reflected from the second side (B)of the stationary document 100 is received by the raster image scanner225, after passing through the second transparent platen 500, the fiberoptic element 400, and the first transparent platen 275.

As noted above, the fiber optic element 400 may be a gradient index lensarray. The fiber optic element 400 may include a lens, such as a SelfocLens and an optical fiber or optical fibers. It is noted that the fiberoptic element 400 may be two separate elements, one element fortransmitting light to the second imaging area, and the other element fortransmitting reflected light from the second imaging area.

It is noted that the gradient index lens array may include a pluralityof light-conducting fibers made of glass or synthetic resin which have arefractive index distribution in a cross section thereof that variesparabolically outward from a center portion thereof. Each fiber acts asa focusing lens to transmit part of an image of an object placed nearone end of the fiber. The assembly of fibers transmits and focusessequential line scans of a document.

It is further noted that the duplex document scanning system may havebeen constructed in an opposite fashion than illustrated by FIGS. 1-3.More specifically, the output tray or output staging area 700 may havebeen positioned below the input tray or input staging area 800. In suchconstruction, the document 100 would move in an opposite direction thandescribed above.

FIG. 4 illustrates another example of a duplex document scanning system.As illustrated in FIG. 4, the duplex document scanning system includes adigital scanning system 200 having a raster image scanner 225 with anaccompanying light source 250. A document 100 is transported from aninput tray or input staging area 8000 to a first imaging area. The lightsource 250 illuminates a first side (A) of the document 100 through atransparent platen 2750. The imaging area includes the transparentplaten 2750 for imaging or scanning the document 100.

The transparent platen 2750 may be a full document platen wherein, afterthe document 100 is placed thereon, the digital scanning system 200 ismoved across the first side (A) of the document 100 to generatesuccessive scanlines of image data.

In a different configuration, the transparent platen 2750 may be apartial document platen wherein the digital scanning system 200 isstationary and the document 100, first side (A) facing the stationarydigital scanning system 200, is moved across, at a constant velocity,the stationary digital scanning system 200 to generate successivescanlines of image data.

The successive scanlines of image data result from light 254 from thelight source 250 illuminating the first side (A) of the document 100,light 256 being reflected therefrom, down through the transparent platen2750, to the raster image scanner 225. The raster image scanner 225 maybe a charge-coupled device or a full-width array.

The duplex document scanning system further includes a looped documentpath 3000 that receives the document 100 exiting the imaging area. Thelooped document path 3000 provides a mechanism for inverting thedocument 100 before the document enters the imaging area a second time.Upon entering the imaging area a second time, a second side (B) of thedocument 100 faces the transparent platen 2750 and the digital scanningsystem 200. Thereafter, the document 100 is transported from the imagingarea to an output tray or output staging area 7000.

It is noted that the duplex document scanning system further includesvarious rollers, nips, and drive motors (not shown) to enable the propertransporting of the document 100 from the input tray or input stagingarea 8000 to an output tray or output staging area 7000.

At either end of the imaging area, as illustrated in FIG. 4, a gate isprovided to direct the movement of the document 100. More specifically,when the document 100 is encountering the imaging area the first time,gates 3500 and 7500 are in a first position. The first position of gates3500 and 7500, as illustrated in FIG. 4, causes the document 100 toproperly exit the imaging area and enter the looped document path 3000.After a trailing edge of the document 100 properly enters the loopeddocument path 3000, the gates 3500 and 7500 are moved to a secondposition. The second position of the gates 3500 and 7500, as illustratedin FIGS. 5 and 6, causes the document 100 to properly exit the loopeddocument path 3000 and enter the imaging area a second time.

The duplex document scanning system also includes a background area orcover 6500 for providing a background to enable document edge detectionby the raster image scanner 225. The background area or cover 6500 mayalso include a calibration target to provide the raster image scanner225 with a reference for “absolute white.”

It is noted that the above-described duplex document scanning systemrequires that a set of duplex originals be placed “face up” in the inputtray and fed in 1 to N order. The multi-page document will then bedelivered “face down” in the output tray but still in the proper order.

It is also noted that duplex document scanning system further includesvarious sensors (not shown) for tracking a position of the document;e.g., sensors for sensing the trailing and leading edges of the document100.

As illustrated in FIG. 4, the document 100 is transported from an inputtray or input staging area 8000 to an imaging area. More specifically,the first side (A) of the document 100 is transported to the transparentplaten 2750. The light source 250 illuminates the first side (A) of thedocument 100, with light 254, through the transparent platen 2750.

In a first configuration, the raster image scanner 225 progressivelyscans, receives reflected light 256, the first side (A) of the document100 as the first side (A) of the document 100 passes over, at a constantvelocity, the stationary raster image scanner 225. In a secondconfiguration, the raster image scanner 225 progressively scans,receives reflected light 256, the first side (A) of the document 100 asraster image scanner 225 passes across the first side (A) of thestationary document 100.

As illustrated in FIG. 5, as the first side (A) of the document 100exits the imaging area, the document 100 enters the looped document path3000. The looped document path 3000 inverts the document 100 withrespect to the raster image scanner 225 without stopping the motion ofthe document 100 or reversal of the forward momentum of the document100.

As illustrated in FIG. 6, the document 100 is transported from an exitof the looped document path 300 to the imaging area for a second time.More specifically, the second side (B) of the document 100 istransported to the transparent platen 2750. The light source 250illuminates the second side (B) of the document 100, with light 254,through the transparent platen 2750.

In a first configuration, the raster image scanner 225 progressivelyscans, receives reflected light 256, the second side (B) of the document100 as the second side (B) of the document 100 passes over, at aconstant velocity, the stationary raster image scanner 225. In a secondconfiguration, the raster image scanner 225 progressively scans,receives reflected light 256, the second side (B) of the document 100 asraster image scanner 225 passes across the second side (B) of thestationary document 100. Thereafter, the document 100 is transportedfrom the second imaging area to an output tray or output staging area700.

It is further noted that the duplex document scanning system may havebeen constructed in an opposite fashion than illustrated by FIGS. 4-6.More specifically, the output tray or output staging area 7000 may havebeen positioned below the input tray or input staging area 8000. In suchconstruction, the document 100 would move in an opposite direction thandescribed above.

It will be appreciated that variations of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also thatvarious presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art which are also intended to beencompassed by the following claims.

1. An automatic document handling system, comprising: a first imagingarea; a light source located in proximity to said first imaging area; araster imaging scanning system located in proximity to said firstimaging area; a semicircular document path, located in proximity to saidfirst imaging area, having an entrance and an exit; a second imagingarea located in proximity to said exit of said semicircular documentpath; and a bi-directional fiber optic element located between saidfirst and second imaging areas; said bi-directional fiber optic elementtransmitting light from said light source to said second imaging area;said bi-directional fiber optic element transmitting light reflectedfrom said second imaging area to said first imaging area.
 2. Theautomatic document handling system as claimed in claim 1, wherein saidfirst imaging area includes a first platen area.
 3. The automaticdocument handling system as claimed in claim 2, wherein said secondimaging area includes a second platen area.
 4. The automatic documenthandling system as claimed in claim 1, wherein said raster imagingscanning system includes a full-width array.
 5. The automatic documenthandling system as claimed in claim 1, wherein said raster imagingscanning system includes a charge-coupled device.
 6. The automaticdocument handling system as claimed in claim 1, wherein saidbi-directional fiber optic element is a gradient index lens array. 7.The automatic document handling system as claimed in claim 1, furthercomprising: a fiber optic element located between said first imagingarea and said raster imaging scanning system; said fiber optic elementtransmitting light reflected from said first imaging area to said rasterimaging scanning system.
 8. The automatic document handling system asclaimed in claim 7, wherein said fiber optic element is a gradient indexlens array.
 9. The automatic document handling system as claimed inclaim 1, further comprising: an input tray; and an output tray; saidinput tray being located in a vertical relationship to said output tray.10. The automatic document handling system as claimed in claim 9,further comprising: a third fiber optic element located between saidfirst imaging area and said raster imaging scanning system; said thirdfiber optic element transmitting light reflected from said first imagingarea to said raster imaging scanning system.
 11. The automatic documenthandling system as claimed in claim 1, wherein a document to be scannedmoves across said first and second imaging areas with a constantvelocity.
 12. An automatic document handling system, comprising: a firstimaging area; a light source located in proximity to said first imagingarea; a raster imaging scanning system located in proximity to saidfirst imaging area; a semicircular document path, located in proximityto said first imaging area, having an entrance and an exit; a secondimaging area located in proximity to said exit of said semicirculardocument path; a first fiber optic element located between said firstand second imaging areas; and a second fiber optic element locatedbetween said first and second imaging areas; said first fiber opticelement transmitting light from said light source to said second imagingarea; said second fiber optic element transmitting light reflected fromsaid second imaging area to said first imaging area.
 13. The automaticdocument handling system as claimed in claim 12, wherein said firstimaging area includes a first platen area.
 14. The automatic documenthandling system as claimed in claim 13, wherein said second imaging areaincludes a second platen area.
 15. The automatic document handlingsystem as claimed in claim 12, wherein said raster imaging scanningsystem includes a full-width array.
 16. The automatic document handlingsystem as claimed in claim 12, wherein said raster imaging scanningsystem includes a charge-coupled device.
 17. The automatic documenthandling system as claimed in claim 12, wherein said first fiber opticelement is a gradient index lens array.
 18. The automatic documenthandling system as claimed in claim 12, wherein said second fiber opticelement is a gradient index lens array.
 19. The automatic documenthandling system as claimed in claim 12, further comprising: an inputtray; and an output tray; said input tray being located in a verticalrelationship to said output tray.
 20. The automatic document handlingsystem as claimed in claim 12, wherein a document to be scanned movesacross said first and second imaging areas with a constant velocity.